Oxyhalogenation process using catalyst having porous rare earth halide support

ABSTRACT

An oxidative halogenation process involving contacting a hydrocarbon, for example, ethylene, or a halogenated hydrocarbon with a source of halogen, such as hydrogen chloride, and a source of oxygen in the presence of a catalyst so as to form a halocarbon, preferably a chlorocarbon, having a greater number of halogen substituents than the starting hydrocarbon or halogenated hydrocarbon, for example, 1,2-dichloroethane. The catalyst is a novel composition comprising copper dispersed on a porous rare earth halide support, preferably, a porous rare earth chloride support. A catalyst precursor composition comprising copper dispersed on a porous rare earth oxyhalide support is disclosed. Use of the porous rare earth halide and oxyhalide as support materials for catalytic components is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 10/130,107filed May 14, 2002, now U.S. Pat. No. 6,680,415, which is a 371continuation of PCT Application PCT/US00/31490 filed Nov. 16, 2000,which claims the benefit of U.S. Provisional Application No. 60/166,897,filed Nov. 22, 1999.

BACKGROUND OF THE INVENTION

In a first aspect, this invention pertains to a process of oxidativehalogenation, particularly oxidative chlorination. For the purposes ofthis discussion, the term “oxidative halogenation” is defined as aprocess wherein a hydrocarbon or halogenated hydrocarbon (the “startinghydrocarbon”) is contacted with a source of halogen and a source ofoxygen so as to form a halocarbon having a greater number of halogensubstituents than the starting hydrocarbon. The term “halocarbon” willinclude halogenated hydrocarbons as well as compounds consisting only ofcarbon and halogen atoms. In a second aspect, this invention pertains toa novel catalyst for the oxidative halogenation process. In a thirdaspect, this invention pertains to novel catalyst supports.

Halogenated hydrocarbons, such as 1,2-dichloroethane, 1,2-dibromoethane,dichloropropanes, and dichloropropenes, find utility in numerousapplications, such as in fumigants and in the production of monomersuseful in polymerization processes. 1,2-Dichloroethane, for example,which is manufactured industrially on a scale of several million tonsper year, is converted by thermal dehydrochlorination into vinylchloride monomer(VCM) and hydrogen chloride. VCM is polymerized intopoly(vinyl)chloride (or PVC), a widely used polymer. The hydrogenchloride produced by dehydrochlorination is separated from the VCM andthereafter contacted with ethylene and oxygen in the presence of acatalyst to produce 1,2-dichloroethane. In the prior art, the contactingspecifically of ethylene, hydrogen chloride, and oxygen to form1,2-dichloroethane and water is known as the “oxychlorination reaction.”

The oxychlorination of ethylene is abundantly described in the patentliterature, representative art of which includes U.S. Pat. Nos.3,634,330, 3,658,367, 3,658,934, 5,972,827, GB 1,039,369, and GB1,373,296. The catalyst employed in the oxychlorination of ethylenetypically contains copper chloride or iron chloride, and optionally, oneor more alkali or alkaline earth metal chlorides, and/or optionally, oneor more rare earth chlorides, supported on an inert carrier, typicallyalumina, silica, or an aluminosilicate. Alternatively, the catalystcomponents can be unsupported, but fused into a molten salt.

Oxidative halogenation processes are quite general and can be extendedto a variety of hydrocarbons in addition to ethylene. For example,oxidative chlorination processes are known for the conversion of methaneto chloromethanes, ethane to chloroethanes and chloroethenes, and, byanalogy, higher saturated hydrocarbons to higher chlorohydrocarbons.This chemistry is not unique to chlorine and can also be extendedbroadly to other halogens. Halogen sources can comprise hydrogen halidesand halohydrocarbons having labile halogens.

One disadvantage of prior art oxidative halogenation processes involvestheir production of undesirable oxygenated by-products, such aspartially oxidized hydrocarbons and deep oxidation products (CO_(x)),namely, carbon monoxide and carbon dioxide. Another disadvantage ofprior art oxidative halogenation processes involves their production ofundesirable oxygenated halocarbon by-products, for example,trichloroacetaldehyde (also known as chloral, CCl₃CHO) in the productionof 1,2-dichloroethane. The production of unwanted by-productsirretrievably wastes the hydrocarbon feed and creates product separationand by-product disposal problems. Any reduction in the quantity ofoxygenated products, particularly, oxygenated halocarbons and CO_(x)oxygenates would be highly desirable.

In a different aspect, rare earth compounds are known to be promoters ina diverse assortment of catalyzed organic processes, including, forexample, oxidations, steam reforming, auto emission reduction,esterification, Fischer-Tropsch synthesis, and the aforementionedoxidative halogenation processes. In the general preparation of rareearth-promoted catalysts, a solution containing a soluble rare earthsalt, such as the chloride, is dispersed, for example, by impregnationor ion-exchange, optionally, along with one or more additional catalyticcomponents onto a support or carrier, such as alumina or silica. U.S.Pat. No. 2,204,733 discloses a catalyst containing a compound of copperand a compound of the rare earth group, being prepared by precipitatingthe metals as hydroxides onto a suitable support, or by soaking orimpregnating a support with a solution of copper and rare earth salts,or by precipitating the metals as hydroxides with sodium or potassiumhydroxide. The art, in general, appears to be silent with respect torare earth compounds functioning as catalyst carriers or supports,perhaps because rare earth compounds typically are not found to beporous. Catalyst supports are generally known to require at least someporosity, that is, some void space, such as channels and pores orcavities, which create surface area whereon catalytic metals andcomponents can be deposited.

SUMMARY OF THE INVENTION

In one aspect, this invention is a novel oxidative halogenation processof preparing a halocarbon. The novel process of this invention comprisescontacting a hydrocarbon or halogenated hydrocarbon with a source ofhalogen and a source of oxygen in the presence of a catalyst underprocess conditions sufficient to prepare a halocarbon containing agreater number of halogen substituents than in the starting hydrocarbonor halogenated hydrocarbon, as the case may be, the catalyst comprisingcopper on a porous rare earth halide support. The term “halocarbon” willbe understood as including halogenated hydrocarbons as well as compoundsconsisting only of carbon and halogen atoms.

The oxidative halogenation process of this invention advantageouslyconverts a hydrocarbon or halogenated hydrocarbon in the presence of asource of halogen and a source of oxygen into a halocarbon having anincreased number of halogen substituents as compared with the startinghydrocarbon. Accordingly, the process of this invention can be used, ina preferred embodiment, to oxychlorinate ethylene in the presence ofhydrogen chloride and oxygen into 1,2-dichloroethane. Since the hydrogenchloride may be derived from the dehydrochlorination of1,2-dichloroethane, the process of this invention may be easilyintegrated into a VCM plant, as described hereinabove. As a morepreferred advantage, the process of this invention produces lower levelsof undesirable by-products, particularly CO_(x) oxygenates, namely,carbon monoxide and carbon dioxide, and lower levels of undesirableoxygenated halocarbons, such as chloral, than prior art oxidativehalogenation processes. The reduction in undesirable oxygenatedby-products translates into a higher selectivity to the desiredhalocarbon product, lower waste of hydrocarbon feed, and fewerby-product disposal problems. In addition, the better selectivity to thedesired halocarbon product allows the process to be operated at highertemperatures for higher conversion.

In a second aspect, this invention is a novel composition of mattercomprising copper dispersed on a porous rare earth halide support.

The novel composition of this invention is useful as a catalyst in theoxidative halogenation of hydrocarbons or halogenated hydrocarbons, asexemplified by the oxychlorination of ethylene in the presence of asource of chlorine and oxygen to form 1,2-dichloroethane.Advantageously, the novel catalyst of this invention produces lowerlevels of by-products, particularly CO_(x) oxygenates and oxygenatedhalocarbons, such as chloral, in the aforementioned oxidativehalogenation process. As a second advantage, the unique catalystcomposition of this invention does not require a conventional carrier orsupport, such as alumina or silica. Rather, the catalyst of thisinvention employs a porous rare earth halide, which uniquely functionsboth as the catalyst's support and as a source of a furthercatalytically active (rare earth) component.

In a third aspect, this invention is a second composition of mattercomprising copper dispersed on a porous rare earth oxyhalide support.This second novel composition is a useful catalyst precursor to thecatalyst comprising copper dispersed on the porous rare earth halidesupport, described hereinabove.

In a fourth aspect, this invention claims use of the aforementionedporous rare earth oxyhalide and porous rare earth halide as supports andcarriers for catalytic components. The porous rare earth oxyhalide orrare earth halide can be used as a support for any catalytic metal ormetallic ion in the Periodic Table of the Elements, as well as anyorganic or non-metallic inorganic catalyst component.

The porous rare earth oxyhalide or halide support can be advantageouslyemployed in catalysts which benefit from the promoting effects of rareearth elements and/or in catalysts which require basicity. Unlike mostcatalyst supports of the prior art, the rare earth halide support ofthis invention is soluble in water. Accordingly, should processequipment, such as filters, valves, circulating tubes, and small orintricate parts of reactors, become plugged with particles of a catalystcontaining the rare earth halide support of this invention, then asimple water wash can advantageously dissolve the plugged particles andrestore the equipment to working order. As a further advantage, thenovel rare earth halide and oxyhalide supports of this invention providefor the easy recovery of costly catalytic metals. The recovery simplyinvolves contacting the spent catalyst containing the catalytic metalsand the novel support with acid under conditions sufficient to etch awaythe catalytic metals. Thereafter, the metals can be recovered from theacidic medium, for example, by precipitation. Any portion of the rareearth support dissolved into the acidic medium can also be recovered byre-precipitation with base.

DETAILED DESCRIPTION OF THE INVENTION

In the novel oxidative halogenation process of this invention, ahalocarbon is produced selectively with advantageously low levels ofby-products, such as, CO_(x) oxygenates (CO and CO₂) and oxygenatedhalocarbons, such as, chloral. The novel process of this inventioncomprises contacting a hydrocarbon or halogenated hydrocarbon (the“starting hydrocarbon”) with a source of halogen and a source of oxygenin the presence of a catalyst under process conditions sufficient toprepare a halocarbon having a greater number of halogen substituentsthan the starting hydrocarbon. As mentioned hereinbefore, for thepurposes of this invention, the term “halocarbon” includes halogenatedhydrocarbons, such as 1,2-dichloroethane, as well as compoundsconsisting only of carbon and halogen atoms, such as perchloroethylene.

In a preferred embodiment, the process of this invention is an oxidativechlorination process comprising contacting a hydrocarbon or chlorinatedhydrocarbon with a source of chlorine and a source of oxygen in thepresence of a catalyst under conditions sufficient to prepare achlorocarbon having a greater number of chloro substituents than in thestarting hydrocarbon. In a most preferred embodiment of this invention,the hydrocarbon is ethylene, and the chlorocarbon is 1,2-dichloroethane.

The novel catalyst employed in the oxidative halogenation process ofthis invention comprises copper dispersed on a porous rare earth halidesupport. For the purposes of this invention, porosity is expressed interms of surface area. In a preferred embodiment, the porous rare earthhalide support has a surface area of least 5 m²/g, as determined by theBET (Brunauer-Emmet-Teller) method of measuring surface area, asdescribed by S. Brunauer, P. H. Emmett, and E. Teller, Journal of theAmerican Chemical Society, 60, 309 (1938). In a preferred embodiment,the porous rare earth halide support comprises a porous rare earthchloride.

In another aspect, this invention is a second composition of mattercomprising copper dispersed on a porous rare earth oxyhalide support.This second composition functions as a catalyst precursor, which findsutility in the preparation of the aforementioned rare earth halidecatalyst. In a preferred embodiment, the porous rare earth oxyhalidesupport has a surface area of least 12 m²/g, as determined by the BETmethod. In a more preferred embodiment, the porous rare earth oxyhalidesupport comprises a rare earth oxychloride.

In yet another aspect, this invention claims the use of theaforementioned porous rare earth oxyhalide and porous rare earth halideas a support or carrier for catalytic components.

Hereinafter, the description will be drafted towards the preferredprocess of oxidative chlorination; however, in light of the detaileddescription set forth, one skilled in the art will be able to extend thedescription to oxidative halogenations other than oxidativechlorination.

The hydrocarbon used in the oxidative chlorination process of thisinvention may be any hydrocarbon which is capable of acquiring halogensubstituents in accordance with the process of this invention. Thehydrocarbon may be an essentially pure hydrocarbon or a mixture ofhydrocarbons. The hydrocarbon may be C₁₋₂₀ aliphatic hydrocarbons,including C₁₋₂₀ alkanes or C₂₋₂₀ alkenes, as well as C₃₋₁₂cycloaliphatic hydrocarbons, or C₆₋₁₅ aromatic hydrocarbons. Suitablenon-limiting examples of such hydrocarbons include methane, ethane,propane, ethylene, propylene, butanes, butenes, pentanes, pentenes,hexanes, hexenes, cyclohexane and cyclohexene, as well as benzene andother C₆₋₁₅ aromatics, such as naphthalenes. More preferably, thehydrocarbon is selected from C₁₋₂₀ aliphatic hydrocarbons, even morepreferably, from C₂₋₁₀ alkenes, and most preferably, ethylene.

It is further within the scope of this invention for the hydrocarbonfeed to be substituted with one or more halogen substituents.Preferably, however, the substituted hydrocarbon retains at least one ormore carbon-hydrogen bonds; but as noted hereinbelow, certainhalocarbons that do not contain carbon-hydrogen bonds, such as(perhalo)olefins, may also be suitable. Preferred halogen substituentsinclude fluorine, chlorine, and bromine. More preferred, are fluorineand chlorine. As an example, the starting halogenated hydrocarbon can bea fluorohydrocarbon which is converted via the oxidative chlorinationprocess of this invention into a chlorofluorocarbon. In an alternativeembodiment, a (perfluoro)olefin can be employed as the starting materialand converted into a chlorofluorocarbon.

The source of chlorine, which is employed in the process of thisinvention, can be any chlorine-containing compound, which is capable oftransferring its chlorine to the hydrocarbon feed and providing a sourceof hydrogen to the oxygen feed. Suitable non-limiting examples of thesource of chlorine include hydrogen chloride and any chlorinatedhydrocarbon having one or more labile chlorine substituents (that is,transferable chloro substituents), a non-limiting example of which ismethylene dichloride. Typically, molecular chlorine (Cl₂) is notemployed in the process of this invention, which requires a source ofoxygen and produces water. Preferably, the source of chlorine ishydrogen chloride.

The source of chlorine may be provided to the process in any amountwhich is effective in producing the desired chlorocarbon product.Typically, the source of chlorine is used in an amount equal to thestoichiometric amount required by the oxidative chlorination reaction ofinterest. In the oxychlorination of ethylene with hydrogen chloride andoxygen, for example, the theoretical stoichiometry is the following:

2CH₂=CH₂+4HCl+O₂→2CH₂Cl—CH₂Cl+2H₂O

Consequently, in ethylene oxychlorination according to this invention,typically four moles of hydrogen chloride are employed per mole ofoxygen. The hydrogen chloride and oxygen are employed in amounts whichare ideally selected to facilitate the near complete reaction of bothreagents; but greater and lesser amounts of hydrogen chloride may alsobe found suitable.

The source of oxygen can be any oxygen-containing gas, such as,commercially pure molecular oxygen, or air, or a mixture of oxygen inanother diluent gas which does not interfere with the oxychlorinationprocess, these being mentioned hereinafter. Generally, the feed to theoxidative chlorination reactor is “fuel-rich,” meaning that a molarexcess of starting hydrocarbon is used relative to oxygen. Typically,the molar ratio of starting hydrocarbon to oxygen is greater than 2/1,preferably, greater than 4/1, and more preferably, greater than 5/1.Typically, the molar ratio of hydrocarbon to oxygen is less than 20/1,preferably, less than 15/1, and more preferably, less than 10/1.

Optionally, if desired, the feed, comprising starting hydrocarbon,source of halogen, and source of oxygen, can be diluted with a diluentor carrier gas, which may be any gas that does not substantiallyinterfere with the oxidative chlorination process. The diluent mayassist in removing products and heat from the reactor and in reducingthe number of undesirable side-reactions. Non-limiting examples ofsuitable diluents include nitrogen, argon, helium, carbon monoxide,carbon dioxide, methane, and mixtures thereof. The quantity of diluentemployed typically ranges from greater than 10 mole percent, andpreferably, greater than 20 mole percent, to typically, less than 90mole percent, and preferably, less than 70 mole percent, based on thetotal moles of feed to the reactor, that is, total moles of startinghydrocarbon, source of halogen, source of oxygen, and diluent.

From the foregoing discussion the feedstream to the oxidativechlorination process comprises a mixture of hydrocarbon or halogenatedhydrocarbon, a source of chlorine, a source of oxygen, and optionally, adiluent or carrier gas. Accordingly, due diligence should be taken toavoid explosive mixtures. Towards this end, one skilled in the art wouldknow how to thoroughly evaluate the flammability limits of the specificfeedstream employed.

In a second aspect of the present invention, there is provided acomposition of matter which is useful as a catalyst in theaforementioned oxidative chlorination process. The composition comprisescopper dispersed on a porous rare earth halide support. The rare earthsare a group of 17 elements consisting of scandium (atomic number 21),yttrium (atomic number 39) and the lanthanides (atomic numbers 57-71)[James B. Hedrick, U.S. Geological Survey—Minerals Information—1997,“Rare-Earth Metals”]. Preferably, herein, the term is taken to mean anelement selected from lanthanum, cerium, neodymium, praseodymium,dysprosium, samarium, yttrium, gadolinium, erbium, ytterbium, holmium,terbium, europium, thulium, lutetium, and mixtures thereof. Preferredrare earth elements for use in the aforementioned oxidative chlorinationprocess are those which are typically considered as being single valencymetals. Catalytic performance of porous rare earth halide-supportedcatalysts using multi-valency metals appears to be less desirable thanthose using single valency metals. The rare earth element for thisinvention is preferably selected from lanthanum, neodymium,praseodymium, and mixtures thereof. Most preferably, the rare earthelement used in the catalyst support is lanthanum or a mixture oflanthanum with other rare earth elements.

Preferably, the support is represented by the formula MX₃ wherein M isat least one rare earth element lanthanum, cerium, neodymium,praseodymium, dysprosium, samarium, yttrium, gadolinium, erbium,ytterbium, holmium, terbium, europium, thulium, lutetium, and mixturesthereof; and wherein X is chloride, bromide, or iodide. More preferably,X is chloride, and the more preferred support is represented by theformula MCl₃, wherein M is defined hereinbefore. Most preferably, X ischloride and M is lanthanum, and the rare earth halide support islanthanum chloride.

Typically, the porous rare earth halide support has a BET surface areagreater than 5 m²/g, preferably, greater than 10 m²/g, more preferably,greater than 15 m²/g, even more preferably, greater than 20 m²/g, andmost preferably, greater than 30 m²/g. For these above measurements, thenitrogen adsorption isotherm was measured at 77K and the surface areawas calculated from the isotherm data utilizing the BET method.

In a third aspect of the present invention, there is provided acomposition which is useful as a catalyst precursor to theaforementioned rare earth halide supported catalyst composition. Thecatalyst precursor comprises copper dispersed on a porous rare earthoxyhalide support. Preferably, the support is represented by the formulaMOX, wherein M is at least one rare earth element lanthanum, cerium,neodymium, praseodymium, dysprosium, samarium, yttrium, gadolinium,erbium, ytterbium, holmium, terbium, europium, thulium, lutetium, ormixtures thereof; and wherein X is chloride, bromide, or iodide. Morepreferably, the support is a rare earth oxychloride, represented by theformula MOCl, wherein M is defined hereinbefore. Most preferably, therare earth oxychloride is lanthanum oxychloride, LaOCl.

Typically, the porous rare earth oxyhalide support has a BET surfacearea of greater than 12 m²/g, preferably, greater than 15 m²/g, morepreferably, greater than 20 m²/g, and most preferably, greater than 30m²/g. Generally, the BET surface area is less than 200 m²/g. Inaddition, it is noted that the MOCl phases possess characteristic powderX-Ray Diffraction (XRD) patterns that are distinct from the MCl₃ phases.

In one preferred embodiment of this invention, the catalyst and catalystprecursor compositions are essentially free of alumina, silica,aluminosilicate, and other conventional refractory support materials,for example, titania or zirconia. The term “essentially free” means thatthe conventional support material is present in a quantity less than 1weight percent, more preferably, less than 0.5 weight percent, and mostpreferably, less than 0.1 weight percent, based on the total weight ofthe catalyst or catalyst precursor composition and conventional supportmaterial.

In an alternative embodiment of this invention, the catalyst or catalystprecursor composition, described hereinbefore (including copper on arare earth halide or rare earth oxyhalide support material), may bebound to, extruded with, or deposited onto a conventional support, suchas alumina, silica, silica-alumina, porous aluminosilicate (zeolite),silica-magnesia, bauxite, magnesia, silicon carbide, titanium oxide,zirconium oxide, zirconium silicate, or combination thereof. In thisembodiment, the conventional support is used in a quantity greater than1 weight percent, but less than 50 weight percent, preferably, less than30 weight percent, more preferably, less than 20 weight percent, basedon the total weight of the catalyst or catalyst precursor compositionand conventional support. Even when a conventional support is present,it is still a fact that the copper is predominantly deposited on therare earth oxyhalide or halide support and that the rare earth oxyhalideor halide support remains the predominant bulk material.

It may also be advantageous to include other elements within thecatalyst. For example, preferable elemental additives include alkali andalkaline earths, boron, phosphorous, sulfur, germanium, titanium,zirconium, hafnium, and combinations thereof. These elements can bepresent to alter the catalytic performance of the composition or toimprove the mechanical properties (for example, attrition-resistance) ofthe material. In a most preferred embodiment, however, the elementaladditive is not aluminum or silicon. The total concentration ofelemental additives in the catalyst is typically greater than 0.01weight percent and typically less than 20 weight percent, based on thetotal weight of the catalyst.

In light of the disclosure herein, those of skill in the art willrecognize alternative methods for preparing the support composition ofthis invention. A method currently felt to be preferable for forming thecomposition comprising the porous rare earth oxyhalide (MOX) comprisesthe following steps: (a) preparing a solution of a halide salt of therare earth element or elements in a solvent comprising either water, analcohol, or mixtures thereof; (b) adding a base to cause the formationof a precipitate; and (c) collecting and calcining the precipitate inorder to form the MOX. Preferably, the halide salt is a rare earthchloride salt, for example, any commercially available rare earthchloride. Typically, the base is a nitrogen-containing base selectedfrom ammonium hydroxide, alkyl amines, aryl amines, arylalkyl amines,alkyl ammonium hydroxides, aryl ammonium hydroxides, arylalkyl ammoniumhydroxides, and mixtures thereof. The nitrogen-containing base may alsobe provided as a mixture of a nitrogen-containing base with other basesthat do not contain nitrogen. Preferably, the nitrogen-containing baseis ammonium hydroxide or tetra(alkyl)ammonium hydroxide, morepreferably, tetra(C₁₋₂₀ alkyl)ammonium hydroxide. Porous rare earthoxychlorides may also be produced by appropriate use of alkali oralkaline earth hydroxides, particularly, with the buffering of anitrogen-containing base, although caution should be exercised to avoidproducing the rare earth hydroxide or oxide. The solvent in Step (a) ispreferably water. Generally, the precipitation is conducted at atemperature greater than 0° C. Generally, the precipitation is conductedat a temperature less than 200° C., preferably, less than 100° C. Theprecipitation is conducted generally at ambient atmospheric pressure,although higher pressures may be used, as necessary, to maintain liquidphase at the precipitation temperature employed. The calcination istypically conducted at a temperature greater than 200° C., preferably,greater than 300° C., and less than 800° C., preferably, less than 600°C. Production of mixed carboxylic acid and rare earth chloride saltsalso can yield rare earth oxychlorides upon appropriate decomposition.

A method currently felt to be preferable for forming the catalystcomposition comprising the rare earth halide (MX₃) comprises thefollowing steps: (a) preparing a solution of a halide salt of the rareearth element or elements in a solvent comprising either water, analcohol, or mixtures thereof; (b) adding a base to cause the formationof a precipitate; (c) collecting and calcining the precipitate; and (d)contacting the calcined precipitate with a halogen source. Preferably,the rare earth halide is a rare earth chloride salt, such as anycommercially available rare earth chloride. The solvent and base may beany of those mentioned hereinbefore in connection with the formation ofMOX. Preferably, the solvent is water, and the base is anitrogen-containing base. The precipitation is generally conducted at atemperature greater than 0° C. and less than 200° C., preferably lessthan 100° C., at ambient atmospheric pressure or a higher pressure so asto maintain liquid phase. The calcination is typically conducted at atemperature greater than 200° C., preferably, greater than 300° C., butless than 800° C., and preferably, less than 600° C. Preferably, thehalogen source is a hydrogen halide, such as hydrogen chloride, hydrogenbromide, or hydrogen iodide. More preferably, the halogen source ishydrogen chloride. The contacting with the halogen source is typicallyconducted at a temperature greater than 100° C. and less than 500° C.Typical pressures for the contacting with the source of halogen rangefrom ambient atmospheric pressure to pressures less than 150 psia (1,034kPa).

As noted hereinabove, the rare earth oxyhalide support (MOX) can beconverted into the rare earth halide support (MX₃) by treating the MOXsupport with a source of halogen. Since the oxidative chlorinationprocess of this invention requires a source of chlorine, it is possibleto contact the Cu-loaded MOCl support with a source of chlorine in situin the oxidative chlorination reactor to form the MCl₃-supported Cucatalyst. The in situ method of forming the catalyst can be generalizedto halogen species other than chlorine. The porous rare earth oxyhalidematerial also finds utility as a catalyst support, even under conditionswhich do not convert the oxyhalide to the halide.

The porous oxychloride material, MOX, and the fully chlorided material,MX₃, can be used in any process wherein a catalyst support or carrier isrequired. The porous rare earth oxyhalide or halide can be used as asupport for any catalytic metal or metallic ion in the Periodic Table ofthe Elements, as well as any organic or non-metallic inorganic catalystcomponent. Suitable metals and metallic ions can be selected from Groups1A, 2A, 3B, 4B, 5B, 6B, 7B, 8B, 1B, 2B, 3A, 4A, and 5A of the PeriodicTable, as referenced for example, in Chemistry, by S. Radel and M.Navidi, West Publishing Company, New York, 1990. Preferred processesinclude catalytic processes wherein a rare earth element is desirable asa catalyst or catalyst promoter, including without limitation,oxidations, reductions, hydrogenations, isomerizations, aminations,cracking processes, alkylations, esterifications, and other hydrocarbonconversion processes, such as Fischer-Tropsch syntheses. Theoxyhalogenation process illustrated herein is only one use for the novelsupports described herein; but this illustration should not limit theuse of these supports in other applications. Any contacting method canbe used to deposit or disperse the catalytic component(s) onto theporous supports of this invention, including without limitation,impregnation, ion-exchange, deposition-precipitation, co-precipitation,and vapor deposition. These contacting methods are well-described in thecatalysis art, for example, as may be found in Fundamentals ofIndustrial Catalytic Properties, by Robert J. Farrauto and Calvin H.Bartholomew, Blackie Academic & Professional, an Imprint of Chapman &Hall, London, 1997.

For the instant oxidative chlorination application, the deposition ofcopper onto the catalyst precursor support, MOX, or catalyst support,MX₃, can be accomplished by co-precipitating the copper and lanthanumfrom a solution containing a base in a manner similar to that notedhereinabove in connection with the formation of the support.Alternatively, the copper can be deposited from a copper-containingsolution by impregnation or ion-exchange, or by vapor deposition from avolatile copper compound. Typically, the copper loading is greater than0.01 weight percent, preferably, greater than 1 weight percent, and morepreferably, greater than 5 weight percent, based on the total weight ofthe catalyst or catalyst precursor composition. Typically, the copperloading is less than 30 weight percent, preferably, less than 20 weightpercent, and more preferably, less than 15 weight percent, based on thetotal weight of the catalyst or catalyst precursor composition.

The oxidative chlorination process of this invention can be conducted ina reactor of any conventional design suitable, preferably, for gas phaseprocesses, including batch, fixed bed, fluidized bed, transport bed,continuous and intermittent flow reactors. Any process conditions (forexample, molar ratio of feed components, temperature, pressure, gashourly space velocity), can be employed, provided that the desiredhalocarbon product, preferably chlorocarbon, is selectively obtained.Typically, the process temperature is greater than 150° C., preferably,greater than 200° C., and more preferably, greater than 250° C.Typically, the process temperature is less than 500° C., preferably,less than 425° C., and more preferably, less than 350° C. Ordinarily,the process will be conducted at atmospheric pressure or a higherpressure. Typically then, the pressure will be equal to or greater than14 psia (101 kPa), but less than 150 psia (1,034 kPa). Typically, thetotal gas hourly space velocity (GHSV) of the reactant feed(hydrocarbon, source of halogen, source of oxygen, and any optionaldiluent) will vary from greater than 10 ml total feed per ml catalystper hour (h⁻¹), preferably, greater than 100 h⁻¹, to less than 50,000h⁻¹, and preferably, less than 10,000 h⁻¹.

The chlorocarbon formed in the process of this invention contains agreater number of chlorine substituents than was present in the startinghydrocarbon or starting chlorinated hydrocarbon. The preferredchlorocarbon product is 1,2-dichloroethane. The oxidative chlorinationprocess of this invention produces oxygenated chlorocarbon by-products,such as chloral, in concentrations which are lower by a factor of atleast 20 mole percent to as much as 90 mole percent, as compared withprior art oxychlorination processes. Likewise, the oxychlorinationprocess of this invention produces CO_(x) oxygenates (CO and CO₂) in asignificantly lower quantity than prior art oxychlorination processes,typically in a quantity lowered by a factor of 10.

The following examples are provided as an illustration of the process ofthis invention, the catalyst and catalyst precursor compositions of thisinvention, and the novel supports of this invention. These examplesshould not be construed as limiting the inventions in any manner. Inlight of the disclosure herein, those of skill in the art will recognizealternative embodiments, for example of reactants, process conditions,catalyst species, and support species, which all fall within the scopeof this invention.

EXAMPLE 1

A catalyst precursor composition comprising copper on a porous lanthanumoxychloride support was prepared as follows. Lanthanum chloride (LaCl₃.7 H₂O, 15.0 g) was dissolved in deionized water (150 ml). Ammoniumhydroxide (6 M, 20 ml) was added to the lanthanum chloride solutionquickly with stirring, resulting in a white precipitate. The mixture wascentrifuged and the excess liquid decanted yielding alanthanum-containing gel. Cupric chloride (CuCl₂.2 H₂O, 0.689 g) wasdissolved in ammonium hydroxide (6 M) by using just enough solution todissolve the copper salt. The copper solution was added to thelanthanum-containing gel. The gel was stirred until a homogeneouslycolored, dark blue precipitate was obtained. The precipitate wascalcined at 400° C. for 4 hours to yield a composition (5.35 g)comprising copper (10 mole percent) dispersed on a porous lanthanumoxychloride support. X-ray diffraction data indicated the presence of aquasi-crystalline form of lanthanum oxychloride. The surface area of thecatalyst was 25.8 m²/g, as measured by the BET method.

EXAMPLE 2

The catalyst precursor composition of Example 1 was converted in situinto a catalyst composition of this invention, comprising copperdispersed on a porous lanthanum chloride support. The catalyst was thenevaluated in the oxychlorination of ethylene. A tubular reactor wasloaded with a mixture of catalyst precursor material (0.3208 g,) fromExample 1 and a low surface area alumina diluent (Norton SA5225 alumina;2.3258 g). The catalyst precursor was dried under a flow of argon at200° C. for 1 h, then converted in situ to the active catalyst bytreating the precursor with a mixture of 44.4 mole percent hydrogenchloride, 8.6 mole percent oxygen, and 47.0 mole percent argon for 10minutes at 250° C. and with a weight hourly space velocity of 22 h⁻¹.The weight hourly space velocity is the mass flow rate divided by theweight of the catalyst tested.

An oxychlorination feed was started comprising 18.2 mole percentethylene, 36.3 mole percent hydrogen chloride, 7.0 mole percent oxygen,and 38.5 mole percent argon at 250° C. and a weight hourly spacevelocity of 26 h⁻¹. The reaction was continued for 30 minutes at 250°C., and the temperature was changed to 300° C. under the same feedconditions. Results are set forth in Table 1. The measurements at 300°C. in Table 1 were taken using an average of the performance at 300° C.during a 15 minute period. The reaction feed composition was changed tohave a lower oxygen content, with 16.7 mole percent ethylene, 33.3 molepercent hydrogen chloride, 4.3 mole percent oxygen, and 45.7 molepercent argon at a weight hourly space velocity of 28 h⁻¹. Thetemperature was raised to 350° C. over 30 minutes and then to 400° C.over 30 minutes. Data in Table 1 taken at 400° C. were an average of thecomposition during a 15 minute period at 400° C. The gaseous effluentfrom the reactor was analyzed by mass spectrometry using a calibrationmatrix to deconvolute the gas composition from the data. Chloral wasestimated by monitoring the mass peak at 82 a.m.u. Process conditionsand results are set forth in Table 1.

TABLE 1 Oxychlorination of Ethylene to Ethylene Dichloride (EDC)^(a)WHSV T EDC Chloral Example Catalyst (h⁻¹) (° C.) (ml/min) (counts) 2Cu/LaCl₃ 26 300 4.02 8 ″ ″ 28 400 8.86 700 CE-1 Cu/K/Al₂O₃ 78 300 2.84160 ″ ″ 87 400 7.58 900 ^(a)Oxychlorination feedstream composition (molepercentages): at 300° C., 18.2 percent C₂H₆, 36.3 percent HCl, 7.0percent O₂, and 38.5 percent Ar; at 400° C., 16.7 percent C₂H₆, 33.3percent HCl, 4.3 percent O₂, and 45.7 percent Ar. Experiments run atatmospheric pressure.

From Table 1 it is seen that the novel catalyst comprising copper on aporous lanthanum chloride support is capable of oxychlorinating ethylenein the presence of hydrogen chloride and oxygen to 1,2-dichloroethane.As an advantage, only a low level of chloral is produced, especially atthe lower reaction temperature of 300° C.

Comparative Experiment 1 (CE-1)

An oxychlorination of ethylene was conducted in the manner described inExample 2, with the exception that a comparative oxychlorinationcatalyst containing copper (4 weight percent) and potassium (1.5 weightpercent) supported on alumina was used in place of the catalyst ofExample 2. The comparative catalyst (0.1046 g) was mixed with aluminadiluent (2.6639 g), and the mixture was loaded into a reactor similar tothat in Example 2. The oxychlorination process was operated as inExample 2, with the process conditions and results set forth in Table 1.When Comparative Experiment 1 is compared with Example 2 at similarprocess conditions, it is seen that the catalyst of the invention, whichcomprised copper dispersed on a porous lanthanum chloride support,achieved a higher productivity to 1,2-dichloroethane at a significantlylower selectivity to impurity chloral, as compared with the comparativecatalyst.

EXAMPLE 3

The catalyst precursor composition of Example 1 was loaded into a fixedbed reactor, converted into an active catalyst comprising copper on aporous lanthanum chloride support by the in situ method described inExample 2, then tested in the oxychlorination of ethylene. A gas feedcontaining ethylene (53.75 mole percent), oxygen (14.61 mole percent),and hydrogen chloride (29.26 mole percent) was passed over the catalystat atmospheric pressure and at 300° C. Flows were adjusted to yield 50percent conversion of oxygen. The catalyst produced 1,2-dichloroethaneas the dominant product. The total carbon oxides (CO_(x)) produced wasonly 0.8 mole percent of the exit gas. Additionally, since the catalystwas water soluble, the spent catalyst could easily be removed from thereactor and supportive equipment, such as filters and transfer lines, bya simple water wash.

Comparative Experiment 2 (CE-2)

Example 3 was repeated using a comparative oxychlorination catalyst inplace of the catalyst of Example 3. The comparative catalyst, similar tothe catalyst of experiment CE-1, contained copper (5.7 weight percent)and potassium (1.75 weight percent) supported on alumina. Thecomparative catalyst produced 1,2-dichloroethane as the dominantproduct; however, the total carbon oxides (CO_(x)) produced was 4.5 molepercent of the exit gas. When Comparative Experiment 2 was compared withExample 3, it was seen that under similar process conditions thecatalyst of the invention produced significantly less carbon oxides thanthe comparative catalyst.

What is claimed is:
 1. A composition of matter comprising copperdispersed on a porous rare earth halide support.
 2. The composition ofclaim 1 wherein the porous rare earth halide support has a BET surfacearea greater than 5 m²/g.
 3. The composition of claim 2 wherein theporous rare earth halide support has a BET surface area greater than 15m²/g.
 4. The composition of claim 1 wherein the rare earth halidesupport is represented by the formula MX₃, wherein M is at least onerare earth lanthanum, cerium, neodymium, praseodymium, dysprosium,samarium, yttrium, gadolinium, erbium, ytterbium, holmium, terbium,europium, thulium, lutetium, or mixtures thereof; or wherein X ischloride, bromide, or iodide.
 5. The composition of claim 4 wherein X ischloride, M is lanthanum, and the rare earth halide support is lanthanumchloride.
 6. A composition of matter comprising copper dispersed on aporous rare earth oxyhalide support.
 7. The composition of claim 6wherein the porous rare earth oxyhalide support has a BET surface areagreater than 12 m²/g.
 8. The composition of claim 7 wherein the porousrare earth oxyhalide support has a BET surface area greater than 20m²/g.
 9. The composition of claim 7 wherein the rare earth oxyhalidesupport is represented by the formula MOX, wherein M is at least onerare earth lanthanum, cerium, neodymium, praseodymium, dysprosium,samarium, yttrium, gadolinium, erbium, ytterbium, holmium, terbium,europium, thulium, lutetium, or mixtures thereof; or wherein X ischloride, bromide, or iodide.
 10. The composition of claim 9 wherein Xis chloride, M is lanthanum, and the rare earth oxyhalide support islanthanum oxychloride.
 11. A method of using a porous rare earth halideas a catalyst support comprising depositing one or more catalyticcomponents onto the porous rare earth halide support.
 12. The method ofclaim 11 wherein one or more metals or metallic ions are deposited ontothe porous rare earth halide support, the metals or metallic ions beingthe elements of Groups 1A, 2A, 3B, 4B, 5B, 6B, 7B, 8B, 1B, 2B, 3A, 4A,or 5A of the Periodic Table.
 13. A method of using a porous rare earthoxyhalide as a catalyst support comprising depositing one or morecatalytic components onto the porous rare earth oxyhalide support. 14.The method of claim 13 wherein one or more metals or metallic ions aredeposited onto the rare earth oxyhalide support, the metals or metallicions being the elements of Groups 1A, 2A, 3B, 4B, 5B, 6B, 7B, 8B, 1B,2B, 3A, 4A, or 5A of the Periodic Table.
 15. The method of claim 13wherein after one or more catalytic components are deposited onto therare earth oxyhalide support, the support is contacted with a source ofhalogen under conditions sufficient to convert the rare earth oxyhalidesupport to a rare earth halide support.
 16. The method of claim 15wherein the source of halogen is hydrogen chloride or molecularchlorine.